The prior art has disclosed many devices for applying a coating to a moving ribbon of material. In particular, the prior art has disclosed many apparatus for applying a metal oxide coating to a moving ribbon of glass, the glass having been manufactured in a float glass furnace. Typical of these showings are the showings of U.S. Pat. Nos. 3,660,061 for a "Coated Glass Sheet and Method of Making the Same"; and 3,796,184 for "Reciprocating Device Having Vibration Reducing Means".
The two cited patents are typical of the structures known in the art in that they show a single spray zone being moved back and forth across a ribbon of glass to be treated. The single spray zone may have one or more spray heads. However, these cited patents typify the many patents which show the use of a single spray zone being moved alternately from right to left and from left to right across a ribbon of hot glass in order to apply materials thereto which disintegrate by heat to form a metallic oxide coating on the glass surface.
It is a primary object of this invention to provide detailed spraying methods which are more efficient in depositing a metallic oxide film on a moving ribbon of glass of varying thickness. A unique method is set forth for each thickness.